Re: [PATCH] cpuset: Add a missing unlock in cpuset_write_resmask()
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2011-02-28 23:56:03
Also in:
lkml
On Thu, 24 Feb 2011 14:58:58 +0800 Li Zefan [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Don't forget to release cgroup_mutex if alloc_trial_cpuset() fails. Signed-off-by: Li Zefan <redacted> --- kernel/cpuset.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-)diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 1ca786a..6272503 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c@@ -1561,8 +1561,10 @@ static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft, return -ENODEV; trialcs = alloc_trial_cpuset(cs); - if (!trialcs) + if (!trialcs) { + cgroup_unlock(); return -ENOMEM; + } switch (cft->private) { case FILE_CPULIST:
It would be better to avoid multiple returns - it leads to more maintainable code and often shorter code:
--- a/kernel/cpuset.c~cpuset-add-a-missing-unlock-in-cpuset_write_resmask-fix
+++ a/kernel/cpuset.c@@ -1562,8 +1562,8 @@ static int cpuset_write_resmask(struct c trialcs = alloc_trial_cpuset(cs); if (!trialcs) { - cgroup_unlock(); - return -ENOMEM; + retval = -ENOMEM; + goto out; } switch (cft->private) {
@@ -1579,6 +1579,7 @@ static int cpuset_write_resmask(struct c } free_trial_cpuset(trialcs); +out: cgroup_unlock(); return retval; }
_ also, alloc_trial_cpuset() is a fairly slow-looking function. cpuset_write_resmask() could run alloc_trial_cpuset() before running cgroup_lock_live_group(), thereby reducing lock hold times. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>